Gas Piping - Weil-McLain SlimFit 2 Series Manual

SlimFit ® Series 2

Gas piping

DO NOT connect the SlimFit boiler to a propane sup-
ply. The boiler is suitable for firing ONLY natural gas.
Failure to comply could result in severe personal injury,
death or substantial property damage.
Connecting gas supply piping
1. See Figure 47.
2. Connect gas supply piping to the boiler.
a. Install a union for servicing, when required.
b. Install a manual shutoff valve in the gas supply piping,
within 6 feet of the boiler.
c. In Canada, the manual gas valve must be identified by
the installer.
3. Support gas piping with hangers or other devices, not by the boiler
or its accessories.
4. Use pipe dope compatible with propane gases (because natural gas
may contain some propane). Apply sparingly only to male threads
of pipe joints so that pipe dope does not block gas flow.
Failure to apply pipe dope as detailed above can result in
severe personal injury, death or substantial property dam-
age.
Install a 100% lockup gas pressure regulator in the gas
supply line if inlet pressure can exceed 14" w.c. at any
time. Adjust the lockup regulator for 7 to 10" w.c. static
inlet pressure. This setting provides a cushion below the
setting of the high gas pressure switch. Failure to comply
could result in shutdown by the high gas pressure switch,
resulting in possible serious property damage due to
freeze-up.
Check gas supply
1. Purge all air from the gas supply piping.
2. Before placing the boiler in operation, check the boiler and its gas
connection for leaks.
a. Close manual main shutoff valve during any pressure
testing at less than 20" w.c.
b. Disconnect the boiler gas connection from the gas supply
piping during any pressure testing greater than 20" w.c.
Do not check for gas leaks with an open flame — use a
soapy water bubble test. Failure to eliminate gas leaks
can cause severe personal injury, death or substantial
property damage.
Check gas supply pressure
1. See Figure 48. Connect a manometer or pressure gauge to the
1/8-inch Port 2 on the side of the gas valve (available on both
sides of valve).
2. The pressure required at gas valve inlet pressure port (verify
minimum gas pressure when all gas appliances are in operation):
a. Minimum gas pressure, with gas flowing — 3" w.c.
(76 mm) — verify during boiler startup, while boiler is
at high fire.
b. Maximum: certified to 14" w.c. (355 mm) with no flow
(lockup) or with boiler on. Set the supply gas pressure
regulator so the supply pressure is far enough below
14" w.c. to ensure that varying pressure conditions
won't trip the high gas pressure switch (set at 14" w.c.).
Part number 550-100-561/0224
commercial condensing gas
- — Boiler Manual
fired water boiler
Figure 47
Connect gas supply piping (all fittings and
gas valve supplied by installer)
Figure 48
Gas valve inlet pressure tap (available on
both sides of the gas valve)
Use port 2 (center) for inlet Use port 2 (center) for inlet
gas pressure measurement gas pressure measurement
Use two wrenches when tightening
gas piping at boiler
, using one wrench
to prevent the boiler gas line connection
from turning. Failure to support the boiler
gas connection pipe to prevent it from
turning could damage gas line compo-
nents.
From gas supply From gas supply
Manual gas valve Manual gas valve
Union Union
Drip leg Drip leg
45